Brussels is also looking at whether the company imposed unfair prices on its customers by linking the cost of its gas to oil prices.

If the charges are proven there could be fines of 11 billion euros for the state owned gas export monopoly, which supplies a quarter of Europe’s needs.

The EU investigation started a year ago and covers Estonia, Latvia, Lithuania, Poland, the Czech Republic, Slovakia, Hungary and Bulgaria.

It has included raids of several offices of Gazprom and its clients.

Speaking at a conference in the Lithuanian capital Vilnius, Almunia said the EU’s executive was preparing a charge sheet against Gazprom, known as a statement of objections.

“It would be premature to anticipate when the next steps would be taken in this investigation, but we have now moved to the phase of preparing a statement of objections,” he told an event organised by the Lithuanian Competition Authority.